This invention relates to silicone hydrogels that contain internal wetting agents, as well as methods for their production and use.
Contact lenses have been used commercially to improve vision since at least the 1950s. The first contact lenses were made of hard materials and as such were somewhat uncomfortable to users. Modern lenses have been developed that are made of softer materials, typically hydrogels and particularly silicone hydrogels. Silicone hydrogels are water-swollen polymer networks that have high oxygen permeability and surfaces that are more hydrophobic than hydrophilic. These lenses provide a good level of comfort to many lens wearers, but there are some users who experience discomfort and excessive ocular deposits leading to reduced visual acuity when using these lenses. This discomfort and deposits has been attributed to the hydrophobic character of the surfaces of lenses and the interaction of those surfaces with the protein, lipids and mucin and the hydrophilic surface of the eye.
Others have tried to alleviate this problem by coating the surface of silicone hydrogel contact lenses with hydrophilic coatings, such as plasma coatings Uncoated lenses having low incidences of surface deposits are not disclosed.
Incorporating internal hydrophilic agents (or wetting agents) into a macromer containing reaction mixture has been disclosed. However, not all silicone containing macromers display compatibility with hydrophilic polymers. Modifying the surface of a polymeric article by adding polymerizable surfactants to a monomer mix used to form the article has also been disclosed. However, lasting in vivo improvements in wettability and reductions in surface deposits are not likely.
Polyvinylpyrrolidone (PVP) or poly-2-ethyl-2-oxazoline have been added to a hydrogel composition to form an interpenetrating network which shows a low degree of surface friction, a low dehydration rate and a high degree of biodeposit resistance. However, the hydrogel formulations disclosed are conventional hydrogels and there is no disclosure on how to incorporate hydrophobic components, such as siloxane monomers, without losing monomer compatibility.
While it may be possible to incorporate high molecular weight polymers as internal wetting agents into silicone hydrogel lenses, such polymers are difficult to solubilize in reaction mixtures which contain silicones. In order to solubilize these wetting agents, silicone macromers or other prepolymers must be used. These silicone macromers or prepolymers must be prepared in a separate step and then subsequently mixed with the remaining ingredients of the silicone hydrogel formulation. This additional step (or steps) increases the cost and the time it takes to produce these lenses. Moreover, these approaches have failed to produce a ophthalmic device which is sufficiently wettable to allow its use as a contact lens without a coating.
Therefore it would be advantageous to find a lens formulation that does not require the use of silicone macromers or other prepolymers and is suitable for extended wear without a surface treatment.
The present invention relates to wettable silicone hydrogels formed from a reaction mixture comprising, consisting essentially of or consisting of at least one high molecular weight hydrophilic polymer and at least one hydroxyl-functionalized silicone-containing monomer.
The present invention further relates to biomedical devices formed from a reaction mixture comprising, consisting essentially of, or consisting of a high molecular weight hydrophilic polymer and an effective amount of an hydroxyl-functionalized silicone-containing monomer.
The present invention further relates to a method of preparing a biomedical device comprising, consisting essentially of or consisting of mixing a high molecular weight hydrophilic polymer and an effective amount of a hydroxyl-functionalized silicone-containing monomer to form a clear solution, and curing said solution.
The present invention yet further relates to a method comprising, consisting essentially of or consisting of the steps of (a) mixing a high molecular weight hydrophilic polymer and an effective amount of an hydroxyl-functionalized silicone-containing monomer and (b) curing the product of step (a) to form a biomedical device.
The present invention yet further relates to a method comprising, consisting essentially of or consisting of the steps of (a) mixing a high molecular weight hydrophilic polymer and an effective amount of a hydroxyl-functionalized silicone containing monomer and (b) curing the product of step (a) at or above a minimum gel time, to form a wettable biomedical device.
The present invention still further relates to a method for improving the wettability of an ophthalmic device formed from a reaction mixture comprising, consisting essentially of and consisting of adding at least one high molecular weight hydrophilic polymer and an effective amount of at least one compatibilizing monomer to said reaction mixture.
The present invention still further relates to a method for improving the wettability of an ophthalmic device formed from a reaction mixture comprising, consisting essentially of and consisting of adding at least one high molecular weight hydrophilic polymer and an effective amount of at least one hydroxyl-functionalized silicone containing monomer to said reaction mixture.
The present invention still further relates to a biomedical device formed from a reaction mixture comprising, consisting essentially of and consisting of at least one hydroxyl-functionalized silicone-containing monomer and an amount of high molecular weight hydrophilic polymer sufficient to provide said device, without a surface treatment, with an advancing contact angle of less than about 80xc2x0, less than about 70xc2x0 or less than about 60xc2x0.
The present invention still further relates to an ophthalmic device formed from a reaction mixture comprising, consisting essentially of or consisting of at least one hydroxyl-functionalized silicone-containing monomer and an amount of high molecular weight hydrophilic polymer sufficient to provide said device, without a surface treatment, with a tear film break up time after about one day of wear of at least about 7 seconds or equal to or greater than tear film break up time for an ACUVUE(copyright) contact lens.
A device comprising a silicone hydrogel contact lens which is substantially free from surface deposition without surface modification